Electrical response to sound stimuli are generated by human brainstem structures. These responses are of 2 types; those evoked by clicks (BER) and those by tones (FFR). Both are the subject of this research. One of our goals is to compare the BER and FFR obtained from normal infants, children and adults with those of clinical patients in the same age groups, and to identify the pathology-dependent differences that will be useful in clinical situations. The other goal is to design and construct an inexpensive portable device for making such measurements in hospital and private-office settings. BIBLIOGRAPHIC REFERENCES: Galambos, R. and K. Hecox. Clinical applications of the brain stem auditory evoked potentials. In: J.E. Desmedt (Ed.) Auditory Evoked Potentials in Man. Prog. Clin. Neurophysiol., Vol. 2. Karger, Basel, 1977. Mokotoff, B., C. Schulman-Galambos and R. Galambos. Brain stem auditory evoked responses in children. Arch. Otolaryngol. 103: 38-43, 1977.